Hi. I managed to write a Gentoo Linux MPI program in C which was chugging along nicely. I have a BASH file which is submitting executions. Each execution was running along nicely, spitting out 100,000 line data files in about 7 minutes each. Suddenly, during one of the jobs, it seemed to stop. Closer investigation reveals that it is now generating about 100 lines of data every minute - that's quite the slowdown. What can cause this? Where do I begin looking to get this running again?

Note that we do not have a job scheduler (or whatever they're called) - and there is no option to install one.

Edit: Oh, and I checked that there is still enough disk space (see https://forums.gentoo.org/viewtopic.php?p=7338412) - there's plenty._________________Depserately needs help learning Gentoo Linux in order to use a 32-node cluster for my master's thesis in mathematics.

Is it processing very small numbers (decaying exponentials, convergence to zero type of stuff)?

On some processors, the hardware floating-point doesn't handle "denormal numbers", so when one is encountered, it traps out to the OS for emulation. If many numbers are denormal, this would slow things down a lot.

(Denormals are different from 0 but smaller than the minimum exponent can represent. "Small" means less than (in magnitude) 2^-1022 for double; 2^-125 for float.)

A remedy for the slow-denormals problem - if less precise small-magnitude calculations are acceptable - is to turn on the flush-to-zero option in the floating point control word. I don't recall offhand how. Post back if you think this is the problem you're having; or search for it._________________The reason there appears to be no god in the world, is because he's overwhelmed constantly pulling all those miracles that are needed to keep all the software we're using, mostly working.

I don't think that's the problem. The program is solving a second order ODE with values that fluctuate between -1 and 1.

I think it could be a load problem. I suspect, some other student - besides me, that is - is not spending his (or her) Saturday night out chasing girls (or guys - or whatever they prefer). And this despite the nice weather here. Who the heck spends their Saturday night programming (when I have a thesis to work on)?

I found the top command and see that someone has 16 jobs sitting above mine on one of the processors! _________________Depserately needs help learning Gentoo Linux in order to use a 32-node cluster for my master's thesis in mathematics.